yeah mine did that too after a rebuild definately the seals and tcdave, to change the seals you need to pull the plastic cover off on the left side where the shifter is and loosten the flywheel nut (i use an air impact wrench) and use a puller to take it off. behind that is your seal. you can remove it esily by drilling two holes in it and putting in wood screws and pulling it out.
the right side you start by taking off the kicker then take out the screws holding the clutch cover on. then unscrew the 5 screws on the clutch to take out the springs. take off the pressure plate, take out the clutch plates, and take off the big metal nut on the pushrod. bend the metal retainer thingy on the clutch basket nut to get it out of the way and then take the nut off with the impact wrench. next there is another gear that is in the way thatis next to the clutch, so take that off. the seal is behind the gear closest to the front of the motor on the crankshaft so unscrew the nut that holds it on, take off the plate holding the old seal on and pull it out.
when you put it back together make sure the dots on the clutch basket and pressure plate line up before you put the springs on. also when you put the flywheel back on make sure not to lose the semicircle shaped woodruff key and remember to put it back on or your quad may run backwards when you start it lol.
good luck and hope this helps!!